A Comparison of Nuclear Thermal to Nuclear Electric Propulsion for Interplanetary Missions. Mike Osenar Mentor: LtCol Lawrence. Overview. Introduction Objective Establish parameters NTR Design NEP Design Discussion and Conclusion. Introduction.
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A Comparison of Nuclear Thermal to Nuclear Electric Propulsion for Interplanetary Missions
Mike Osenar
Mentor: LtCol Lawrence
Method: take a set of inputs, use a series of calculations and SPAD process along with reasonable design assumptions to design a spacecraft to reach a given ΔV
Ariane 5 Payload Specifications
Design points established from Dumbkopff charts
Size system so that it meets 3 specifications
Inputs from Dumbkopff: finert, ΔV
Assumptions
Po = 7 MPa
Isp = 1000 s – hydrogen
Tc = 3200 K
T/W = .3 – experimented, balance between high thrust short burn time and low reactor mass (low power)
Subsystem Sizing (note: volume constraint height)
Payload
1000 kg to Jupiter, 500 to Pluto
based on densities of actual space mission
sized as 2 m tall cylinder
Tank
biggest part – hydrogen has low density
Turbo Pump Feed System
Nuclear Reactor
Radiation Shield
standard SPAD design – 18 cm Be, 5 cm W, 5 cm LiH2
Nozzle
Columbium, designed to be ideally expanded in space (ε=100)
Miscellaneous
Avionics
Reactor containment vessel
Attitude thrusters
Structural mass
Payload
Propellant Tank
Pump
Shield
Reactor
Nozzle
Achievable ΔV verified with Rocket Equation
Vehicle height determined by stacking parts according to Figure
Final Results of NTR Design
Size system so that it meets 2 specifications
No size requirement – analysis showed that NEP systems would violate mass constraints before volume – no low-density hydrogen propellant
Power Source
Subsystem Design
NEP Design Results
NTR Design
NEP Design
Questions?